This invention relates to a load bearing structural member, a frame structure and a vehicle chassis.
Conventionally vehicle chassis for commercial vehicles are generally steel "ladder frame" constructions which are torsionally very flexible and reliance is placed upon this flexibility to contribute to the vehicle suspension. It has never proved commercially satisfactory to make such a chassis of light metal alloys such as aluminium alloys largely because fatigue problems generated at all the joints have been difficult to overcome. Nevertheless there is considerable pressure to make use of light metal and particularly aluminium alloys both in view of their greater corrosion resistance and also to save weight.
In recent years important developments have taken place in suspension systems particularly pneumatically operated systems, and these have now reached a point of design where it is beneficial to use a much more torsionally stiff chassis structure.
Thus a vehicle chassis can now be as rigid as it is possible to make it commensurate with other design constraints and it is an object of the present invention to provide an improved load bearing member of light metal such as an aluminium alloy; a frame structure incorporating two such members and a vehicle chassis comprising the frame structure.